Vince Zampella has confirmed the Titanfall download for PC will be approximately 21GB in size, and take up around 48GB when fully installed.
Vince was asked on Twitter by an eager fan who enquired about the download and installation size for the PC.
@Ahmed_Zainal approx: 21gb download, 48gb installed.
— Vince Zampella (@VinceZampella) February 24, 2014
Source: Twitter via Reddit